The upcoming Bones/Family Guy crossover is being promoted as something big and new because it’s an animated character appearing on a live-action show. But really it’s a very old-fashioned crossover where characters from one long-running show pop up on another long-running show on the same network. Though I guess Family Guy is more popular than Bones, this isn’t really the sort of crossover that’s done to boost a show’s popularity. It’s more the sort of crossover that happens when two shows are produced by the same studio, and so when the live-action show wants to do an animated segment, they arrange to borrow a character from their sister show.
It used to happen quite often in the movies; Bugs Bunny appeared in two live-action musicals at Warner Brothers, Two Guys From Texas and My Dream Is Yours, Tom and Jerry swam with fellow MGM contractee Esther Williams, and most famously, Jerry appeared with Gene Kelly in Anchors Aweigh after Disney refused permission to loan out Mickey Mouse. A scene which, to bring us full circle, was copied by Family Guy, because why make new animation when you can just trace over the old animation and claim you’re doing an homage?